After updating from Beta20 to 21, the editor crash when build my proyect. (All the crash are without option to report crash, or any information about the crash, only sudden close of the editor)
After many tries, I have isolated the problem to a prefab that contains some ui component. (not all prefabs failed)
If I select that prefab, the editor crash.
Can you please log this as a bug for us to investigate.
The bug report has been sent (by mail, the bug report option failed), with the prefab that crash (tested on a clean project)